/*
* Copyright 2002-2006 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.osgi.context;
import java.io.IOException;
import java.net.URL;
import java.util.Enumeration;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractRefreshableApplicationContext;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.osgi.context.support.BundleContextAwareProcessor;
import org.springframework.util.StringUtils;
/**
*
* AbstractRefreshableApplicationContext subclass that implements the
* ConfigurableOsgiApplicationContext interface for OSGi environments.
* Pre-implements a "configLocation" property, to be populated through the
* ConfigurableOsgiApplicationContext interface on OSGi bundle startup.
*
* <p>
* This class is as easy to subclass as AbstractRefreshableApplicationContext:
* All you need to implement is the <code>loadBeanDefinitions</code> method;
* see the superclass javadoc for details. Note that implementations are
* supposed to load bean definitions from the files specified by the locations
* returned by the <code>getConfigLocations</code> method.
*
* <p>
* Interprets resource paths as OSGi bundle resources (either from the bundle
* classpath or OSGi entries).
*
* <p>
* In addition to the special beans detected by AbstractApplicationContext, this
* class registers the <code>BundleContextAwareProcessor</code> for processing
* beans that implement the <code>BundleContextAware</code> interface.
*
*
* <p>
* Note that OsgiApplicationContext implementations are generally supposed to
* configure themselves based on the configuration received through the
* ConfigurableOsgiBundleApplicationContext interface. In contrast, a standalone
* application context might allow for configuration in custom startup code (for
* example, GenericApplicationContext).
*
* @author Costin Leau
* @author Adrian Colyer
*
*/
public abstract class AbstractRefreshableOsgiBundleApplicationContext extends AbstractRefreshableApplicationContext
implements ConfigurableOsgiBundleApplicationContext {
/** OSGi bundle - determined from the BundleContext */
private Bundle bundle;
/** OSGi bundle context */
private BundleContext bundleContext;
/** Path to configuration files * */
private String[] configLocations;
/** Internal ResourceLoader implementation used for delegation * */
private OsgiBundleResourceLoader osgiResourceLoader;
public AbstractRefreshableOsgiBundleApplicationContext() {
setDisplayName("Root OsgiBundleApplicationContext");
}
public AbstractRefreshableOsgiBundleApplicationContext(ApplicationContext parent) {
super(parent);
}
/**
* Set the bundleContext for this application context. Will automatically
* determine the bundle, create a new ResourceLoader (and set its classloader to
* a custom implementation that will delegate the calls to the bundle).
*/
public void setBundleContext(BundleContext bundleContext) {
this.bundleContext = bundleContext;
this.bundle = bundleContext.getBundle();
this.osgiResourceLoader = new OsgiBundleResourceLoader(this.bundle);
this.setClassLoader(createBundleClassLoader(this.bundle));
}
/**
* Get the OSGi BundleContext for this application context
*/
public BundleContext getBundleContext() {
return this.bundleContext;
}
public Bundle getBundle() {
return this.bundle;
}
public void setConfigLocations(String[] configLocations) {
this.configLocations = configLocations;
}
protected String[] getConfigLocations() {
return this.configLocations;
}
/**
* Sets a default config location if no explicit config location specified.
*
* @see #getDefaultConfigLocations
* @see #setConfigLocations
*/
public void refresh() throws BeansException {
if (this.configLocations == null || this.configLocations.length == 0) {
setConfigLocations(getDefaultConfigLocations());
}
super.refresh();
}
/**
* Return the default config locations to use, for the case where no
* explicit config locations have been specified.
* <p>
* Default implementation returns null, requiring explicit config locations.
*
* @see #setConfigLocations
*/
protected String[] getDefaultConfigLocations() {
return null;
}
/**
* Register post processor for BeanContextAware beans.
*/
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
super.postProcessBeanFactory(beanFactory);
beanFactory.addBeanPostProcessor(new BundleContextAwareProcessor(this.bundleContext));
beanFactory.ignoreDependencyInterface(BundleContextAware.class);
}
/**
* This implementation supports pattern matching inside the OSGi bundle.
*
* @see OsgiBundleResourcePatternResolver
*/
protected ResourcePatternResolver getResourcePatternResolver() {
return new OsgiBundleResourcePatternResolver(this);
}
// delegate methods to a proper OsgiResourceLoader
public ClassLoader getClassLoader() {
return osgiResourceLoader.getClassLoader();
}
public Resource getResource(String location) {
return osgiResourceLoader.getResource(location);
}
public void setClassLoader(ClassLoader classLoader) {
osgiResourceLoader.setClassLoader(classLoader);
}
protected Resource getResourceByPath(String path) {
return osgiResourceLoader.getResourceByPath(path);
}
/**
* Create the classloader that delegates to the underlying OSGi bundle.
*
* @param bundle
* @return
*/
protected ClassLoader createBundleClassLoader(Bundle bundle) {
return new BundleClassLoader(bundle);
}
/**
* Proxy classloader (delegating classLoader calls to the underlying
* bundle).
*
*/
private static class BundleClassLoader extends ClassLoader {
private Bundle backingBundle;
public BundleClassLoader(Bundle aBundle) {
this.backingBundle = aBundle;
}
protected Class findClass(String name) throws ClassNotFoundException {
return this.backingBundle.loadClass(name);
}
protected URL findResource(String name) {
return this.backingBundle.getResource(name);
}
protected Enumeration findResources(String name) throws IOException {
return this.backingBundle.getResources(name);
}
}
/**
* Return diagnostic information.
*/
public String toString() {
StringBuffer sb = new StringBuffer(super.toString());
sb.append("; ");
sb.append("config locations [");
sb.append(StringUtils.arrayToCommaDelimitedString(this.configLocations));
sb.append("]");
return sb.toString();
}
}